Lume on a dial can be an underappreciated part of the design and construction of a watch. Observable only in darkness, the brand and intensity of lume isn’t always considered when you’re choosing a watch. We think more attention should be paid to what lume adds to a dial. Now, with #lumeshot becoming a regular feature on social media, we’re finally seeing more of those lume shots we love. Whether your lume glows blue, green, or somewhere in between, you may be curious about the different types of lumes available on Rolex watches. Here’s our guide to identifying the lume on your Rolex, as well as a few key facts about the history and function of Rolex’s lume materials through the years.
At the turn of the century, the miraculous properties of radioactive materials were preached far and wide. People believed radioactive materials could increase fertility and cure everything from cancer to indigestion. The otherworldly glow that radium emitted was used to illuminate airplane instruments, added to beauty products, and painted on watch dials to impart glow-in-the-dark properties to watches, making them readable in darkness.
Within a few years, however, scientists began to recognize the danger of radioactive isotopes, and radium was outlawed for commercial use. Radium luminescence was soon replaced with tritium, a much weaker radioactive material that was safe to use on watch dials. Tritium was used by Rolex into the late 1990s, and older dials that use tritium lume often fade to a tan color on the indices. For vintage watch collectors, these faded indices retain a very specific appeal.
Luminova and Super-Luminova
In 1998, Rolex began using Luminova for the lume on its watch dials, a non-radioactive compound manufactured by Nemoto & Co., Ltd. By 2000, Rolex had switched to Nemoto & Co’s Super-Luminova, a strontium aluminate lume. This lume compound stores photons when exposed to sunlight or artificial light, allowing it to glow in darkness for hours after initial light exposure. In low light, Super-Luminova glows green, and this particular color soon became associated with the Rolex brand. While some collectors love the powerful bright blue Chromalight on new references, there’s a vocal contingent of Super-Luminova fans who prefer the more subtle green glow. If that’s the case for you, there are plenty of slightly older references that retain Super-Luminova as the lume of choice. These can be easy to find secondhand online if you find the Chromalight glow too jarring.
One of the most compelling things about Rolex is that it never stops innovating, even in the tiniest components of its creations. Some collectors accuse Rolex of being staid or conservative, but in fact it’s a brand that has worked to innovate nearly every aspect of the modern wristwatch. In 2008, Rolex again reimagined its lume compound, introducing Chromalight on the Deepsea Sea-Dweller.
This was definitely an appropriate choice because of the Deepsea’s association with the deepest, darkest reaches of the ocean. The Deepsea, with its patented Helium Escape Valve, has the deepest depth-rating of any Rolex watch at 3,900 meters below sea level. Rolex presented Chromalight as a lume that could provide a powerful light even thousands of meters underneath the surface. Chromalight has a distinct blue tone that’s hard to miss, and Rolex soon switched to Chromalight on the Submariner, the GMT-Master, the Daytona, and the Explorer. Some Datejusts and the Milgauss still feature Super-Luminova, so it’s not been entirely phased out yet.
Match Your Strap to Your Lume
While some collectors love the powerful bright blue Chromalight on new references, there’s a vocal contingent of Super-Luminova fans who prefer the more subtle green glow. If that’s the case for you, there are plenty of slightly older references that retain Super-Luminova as the lume of choice. These can be easy to find secondhand online if you find the Chromalight glow too jarring. No matter which lume hue you love, you can echo the color by choosing an Everest Band rubber strap in green or blue to match your lume tone.